Since the launch of the dot com domain extension there have been several new extensions introduced. Most notably .org, .net, .biz, .info, in addition to country specific extensions. Many people in the internet marketing community believe that you can rank better in search engine results by having a .com and that.info is very hard to rank with. This is a myth, and has been proven by Google.
When a search engine calculates a sites ranking, it does not take into account the domain extension. You could rank just as well with a.info domain as you could with a.com. The argument used by those who take the opposite view is that whenever you do a search, the.com extensions always appear higher in the search engine results than the.biz and.info sites. Whilst this is true, there is a perfectly valid reason why this generally occurs, and it has nothing to do with the domain extension, and everything to do with the webmaster of that site.
Sites with.com extensions tend to be older, and therefore have built up more content and back links than.biz and.info sites which are newer extensions. Anything other than a.com is likely to be a younger site, and therefore there is less chance that the site will rank well because of this. Google also gives higher rankings to domains that have been registered for a long time. Secondly, .info and.biz sites have been offered on special offer by domain registration sites, sometimes costing as little as 99 cents to register the domain for a year. Understandably, this attracted people on a tiny budget, who were most probably not as committed to making their site a success. As such, their websites where not much to write home about, and accordingly suffered in the search engine rankings.
It is because of these factors alone that it may appear that.biz and.info domains are given lower priority by the search engines, and it has nothing to do with the actual domain extension itself. If you put a content rich site with relevant back links on a.biz or.info domain, it would rank just as well as it would with any other domain extension.
So next time you unearth a niche with great potential, do not abandon it because you can not register one of the 'big three' domain extensions. Take whatever is available, build a great site, and watch the search engine visitors flood in.